Wheel-based vehicle braking systems, or service brakes, apply braking force to slow and/or stop a vehicle's wheels at the direction of the driver or a controller, for example, using brake calipers and brake pads to inhibit rotation of brake rotors in response to actuation of a brake pedal. Anti-lock braking systems (ABS) prevent locking or excessive slipping of the vehicle's wheels during application of service braking force, improving service brake feel and control of the vehicle for the driver. Anti-lock service braking, for example, in the form of modulation of service braking force, can be automatically initiated by an ABS controller based on a threshold difference between wheel speed and vehicle speed over a predetermined time period. That is, anti-lock service braking is implemented when a wheel-slip threshold is reached.
Exhaust-based vehicle braking systems, or exhaust brakes, restrict the flow of exhaust from an engine in order to reduce engine speed and hence propulsion torque supplied by the engine, for example, using a valve within an exhaust component or within a turbocharger component located downstream from the engine. Exhaust braking can be used alone or in combination with service braking, for example, in commercial vehicles, to slow the vehicle more efficiently and increase the life of service braking components. However, existing control features for exhaust braking include only restriction of the maximum level of exhaust braking to avoid wheel slip, activation of exhaust braking only during the presence of traditional service braking, and deactivation of exhaust braking during the presence of anti-lock service braking. More sophisticated control systems for exhaust braking are thus desired.